The power generated by a PV system depends on its orientation relative to the Sun's position. Tracking systems are devices that change the orientation of the solar energy harvesting modules so that the orientation, at each time point, is as close as possible to the Sun's position.
In particular, solar energy harvesting modules consisting of conventional PV panels offer a performance which depends on the angle of incidence of the rays. However, even when this angle is great, the modules continue to harvest power even if to a lesser extent. Other types of solar energy harvesting modules are concentrator modules. These modules do not cover the entire surface irradiated with semiconductor material, but are formed by a surface formed by concentrating lenses that focus the radiation incident on a small area in which the semiconductor or solar cell is located. In general, concentrated PV systems are much more sensitive to deviations from the correct orientation to the Sun. Even with small deviations, the non-targeting of beams incident on the semiconductor can cause a significant drop in the power produced.
The prior art reveals auxiliary devices that measure the targeting error of the system relative to the Sun's position. This measure is interpreted and used by a control means which in turn act on drive means of the tracking device so that the solar energy harvesting modules maintain the correct orientation.
An example auxiliary device is one which makes use of a plurality of solar-radiation-sensitive areas located on a plane and distributed around a point; and an opaque element located on that point, distanced away from the plane, intended to throw shadow on the plane where the sensitive areas are located.
When the orientation of the plane where the solar-radiation-sensitive areas are located is perpendicular to the radiation, then the element found on this plane casts shadow on the point around which the sensitive areas are distributed without any of them undergoing a reduced radiation reading. By contrast, when the plane is not oriented perpendicularly to the direction of radiation, the shadow covers some of the sensitive areas. Depending on which sensitive area is completely or partially covered, it is possible to determine the degree of deviation of the plane orientation of this auxiliary device. Such and other auxiliary devices have several drawbacks. The first is that the dirt could distort the reading, as shadows may be generated being interpreted as deviations from the orientation device. A not very large particle may prevent the correct orientation of an entire solar energy harvesting module and the latter may be installed in a place where it is not easily or immediately accessed.
Another drawback to the use of auxiliary devices that determine the targeting error is that such devices measure the error in orientation with respect to the direction of incidence of the rays and not the error in the orientation of the entire system. It is therefore necessary to ensure that the targeting sensor and the tracker have the same orientation. However, this orientation relative to one another is not always perfect, is subject to assembly errors; and can be modified by problems such as the deformation or misalignment of the structural elements.
The present invention is a method for properly orienting a CPV system without using auxiliary elements to measure the targeting error.